1. Field of the Invention
This invention relates to a dyeing assistant and more particularly to an anti-migration agent for preventing the migration of a dye applied to a cloth to be dyed.
2. Description of the Prior Art
In dyeing a hydrophobic synthetic fiber, sometimes a dye undergoes migration making a uniform dyeing difficult in the drying process after applying a dyeing solution to the fiber cloth. For example, in the thermosol dyeing wherein a polyester cloth is padded with a disperse dye, then dried and thereafter subjected to a dry heat treatment at a high temperature, it is necessary that the drying after padding should be a uniform drying, and even if a uniform drying is applied, there is a problem such that the disperse dye undergoes migration resulting in occurrence of an uneven dyeing. To remedy such a defective dyeing resulting from migration of a dye, there has been adopted the addition of a viscosity intensifier such as sodium alginate. But sodium alginate is expensive and its effect is not yet fully satisfactory.
Also, in dyeing a cellulosic cloth, e.g. cotton and hemp, a uniformly applied dyeing solution sometimes undergoes migration in the drying process. For example, in dyeing a cellulosic cloth with a reactive dye according to the pad dry cure method, there occurs migration of a dye based on uneven drying in the drying process resulting in occurrence of an uneven dyeing. Also in the dyeing according to the vat steam process using a vat dye, the migration of a dye in the drying process causes a defective dyeing. And to prevent such a migration, there has been used sodium alginate.
Thus, the dyeing industry has been harassed by the problem that in the drying process for fixing a dye to a cloth, the dye which has been uniformly applied to the cloth in the preceding stage undergoes migration and is fixed unevenly to the cloth resulting in an uneven dyeing. Therefore, the development of an effective anti-migration agent has been desired.